Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
In general, the design of a rotor blade is limited by a clearance threshold distance from the tower. For example, during operation of the wind turbine, the rotor blades may deflect towards the tower. To reduce the risk of the rotor blades contacting the tower and damaging the wind turbine, various certification rules require that the rotor blades be designed to utilize no more than, for example, approximately two-thirds of a static clearance distance when the rotor blades deflect. The static clearance distance, in general, is the non-deflected distance between the blade tip and the tower.
Thus, the required clearance threshold distance limits the design and performance of generally known rotor blades. Known prior art solutions to this limitation include, for example, incorporating a general flapwise curve into the rotor blade away from the tower, adjusting the tilt angle, coning the hub, and/or coning the rotor blade at the root. However, during extreme deflection of these prior art rotor blades, the rotor blades typically act similarly to beams, with the tips of the rotor blades “opening up” despite the flapwise curve and potentially striking the tower.
Thus, an improved rotor blade for a wind turbine would be desired. Specifically, a rotor blade with improved features for maintaining an appropriate tower clearance while allowing for improved rotor blade performance would be advantageous.